US2204893A

US2204893A - Emergency brake lever assembly

Info

Publication number: US2204893A
Application number: US253295A
Authority: US
Inventors: Alvin L Johnson
Original assignee: American Forging and Socket Co
Current assignee: American Forging and Socket Co
Priority date: 1939-01-28
Filing date: 1939-01-28
Publication date: 1940-06-18
Anticipated expiration: 1957-06-18

Description

June 18, 1940. A L JOHNSGN 2,204,893

EMERGENCY BRAKE LEVER ASSEMBLY Filed Jan. 28, 1939 BYMM (41 63am.

ATTORNEY series.

Patented June 18, 1940 UNITED STATES PATENT OFFICE EMERGENCY BR'AKELEVER ASSEMBLY Application January 28, 1939, Serial No. 253,295

2 Claims. (01. 74-587) 7 Pivotally connected by a rivet 15 adjacent the This invention relates to motor vehicles but more particularly to emergency brake levers therefor.

An object is to produce an efiicient brake lever for automobiles which is easy to operate, simple in construction, and inexpensive to manufacture.

Another object is to produce a hand brake lever assembly which can be readily disengaged from its sector by a very slight movement thereby facilitating release of the brake and obviating the necessity of manually exerting an excessive amount of effort to effect such release.

A further object is to produce a new and improved hand emergency brake lever provided with a so-called delayed action whereby depression of the usual spoon does not retract or render inefiective the locking member until slight movement has first been imparted to the lever in a brake-tightening direction, thereby eliminating the danger of accidental release of the brake.

Further objects of the invention reside in details of construction, assembly and operation hereinafter more fully described.

For purposes of illustration but not of limitation, an embodiment of the invention is shown in the accompanying drawing in which 7 Figure 1 is a side elevation partly in section of a hand emergency brake lever assembly for an automobile;

Figure 2 is a side edge elevation of theassembly shown in Figure 1;

Figure 3 is an enlarged fragmentary side View of the lever and sector, some parts being broken away to show parts more clearly;

Figure 4 is a transverse sectional view on the line 4--4 of Figure 3; and

Figure 5 is an enlarged fragmentary view of a lever showing an alternate form of pawl and ratchet structure. I

The illustrated embodiment of the invention comp-rises a hand emergency brake lever assembly for automobiles and, as shown, a sheet metal mounting plate I!) is formed with holes H to receive bolts for securing the plate to a suitable support, such as a support disposed underneath the instrument board of the car. Forming an integral part of the mounting plate I6 is a sector l2 formed with an arcuate series of relatively shallow grooves l3 alternating with relatively short rounded teeth l4. As more clearly shown on Figure 3, the shallow grooves l3 are rounded and the teeth M which are relatively narrow are each disposed at approximately right angles to the tangent of the arc defined by such arcuate upper end portion of the mounting plate I0 and depending therefrom is a brake lever it which is formed of sheet metal and is provided with a pair of laterally spaced integral arms 17, the upper end portions of which straddle the sector It. The arms are integrally connected by a web I8 which extends from a point beneath the sector 12 to the lower end of the lever. Pivotally connected to the lever l6 and straddling the two arms is a member H? which provides a connection between the lever and suitable brake-operating means (not shown).

Disposed between the arms I1 and pivotally mounted on a rivet 20 is a metal pawl the upper end of which inclines to the left (Figures 1 and 3), or in a direction toward the member l9. The upper end portion of the panel is pointed and the extreme end or nose 22 of the pawl is rounded in the form of a knob to fit nicely into a groove l3. The lower end portion of the pawl 2| below the rivet 20 forms with the upper end portion a substantially obtuse angle and the extreme lower end is formed with a substantially V- shaped notch 23. It will be observed that the rivet 20 on which the pawl 2| is pivoted is juxtaposed to the web portion l8 of the lever.

It will be noted that the lower end portion of the lever [B inclines forwardly as indicated at 24 and the portion of the lever therebeneath, designated by the numeral 25, which provides the hand grip curves downwardly and rearwardly, the metal on the inner side being flanged over as indicated at 26 to provide a comfortable hand hold. Disposed between the arms I! of the lever is a pawl actuating arm 2'! which is pivoted on a rivet 28 disposed above the bend of the lever and in a position juxtaposed to the free edges of the arms I l opposite to the web portion IS. The actuating arm 27 is somewhat C shaped and is formed with a reversely bent lower end 29 providing a thumb-engaging portion which extends through an opening 30 in the wall of the web l8. The arm 21 which is of sheet metal is of U shape in cross section, as shown on Figure 5, and is normally urged in a counterclockwise direction (Figure l) by a helical spring 3|. The lower end of the spring 3| seats on a knob 32 pressed out of the web l8 and the opposite end exerts pressure against the upper end portion of the arm 21, such end fitting over an outwardly turned extension 33 on a spring finger 34. The finger 34 consists of a strip of spring tempered metal which is secured by a rivet 35 intermediate its ends to the upper end portion of the actuating arm 21.

The upper end of the spring finger 34 seats in the inner end of the V-shaped notch 23 of the pawl 2|.

In operation, it will be understood that with the parts in the position shown on Figure l, the nose of the pawl 22 is in engagement with one of the grooves E3. The lever i6 is held by the brake setting stress and movement of the lever to the left of the figure can not be accomplished until the pawl is released from the ratchet. Such release can not be accomplished merely by depressing the thumb piece 29 of the pawl actuating arm 2's. However, depression of the thumb piece 29 exerts a resilient force against the pawl which tends to rock it in a counterclockwise direction away from the ratchet teeth. The spring finger alone is not suincient to accomplish such pawl movement, but upon slight movement of the lever it to the right an amount sufficient to enable the rounded end 22 of the pawl to swing clear of the teeth, the lever is freed from the ratchet. Thus it will be apparent that since the teeth M are quite short a very slight movement of the lever i6 is adequate to release the stress upon the pawl which is quickly and abruptly moved away from the teeth by means of the spring finger 34. Thereupon the lever It can be moved freely in either direction so that the brake can be applied and released readily at will. Upon release of the pawl actuating arm 2? the coil spring 3i operates to rock the pawl 2i through the agency of the arm 2? and finger 3 11 in a clockwise direction into engagement with one of the notches ii on the sector.

An important feature resides in the construction of the ratchet and pawl in such manner that a very slight pull on the lever is adequate to release the pawl but when the pawl is in brake setting position, the parts are securely and rigidly retained in place, the force of the pawl being directed in such manner that substantial metal in the sector sustains the load imposed upon it. It will be observed that the force of the pawl is transmitted to substantially the center of the groove with which it engages, so that the possibility of shearing teeth in the ratchet or the pawl is eliminated. This dispenses with the use of. a sizable tooth on the sector which heretofore has been sheared when an excessive strain is imposed upon it.

Another feature of outstanding importance is that release of the brake can be effected only after positive movement isv imparted to the lever. As heretofore brought out, depression of the pawl actuating arm is not sufiicient to effect brake release so that accidental hitting of the lever will not release the brake. On the contrary, a movement of the lever which is indeed a slight one but nevertheless a positive one, in a brake tightening direction, must be first made before the pawl can possibly be disengaged from the ratchet.

An alternate form is shown on Figure 5 in which the teeth Mia 01" the sector are of the usual type, tapering to a point and providing substantially V-ShEtDSd angularly disposed notches lSa thercbetween. In this instance, the extreme end of the pawl Zia is pointed as indicated at 22a to fit into one of the notches 53a. In this form it will be apparent that a greater movement in brake applying direction must be imparted to plying direction is required to release the pawl whereupon the lever can move freely so long as the pawl actuating arm is depressed. Upon release of the pawl actuating arm the pawl immediately finds its notch whereupon it is held securely in place.

It is to be understood that numerous changes in details of construction, arrangement and operation may be efiected without departing from the spirit of the invention especially as defined in the appended claims.

What I claim is:

1. A brake lever assembly comprising a sector provided. with a ratchet having an arcuate series of alternating notches and teeth, a brake lever pivotally connected at one end to said sector and movable across said ratchet, a pawl pivoted intermediate its ends to said lever and having one end engageable with said ratchet, a pawl actuating trip lever pivoted intermediate its ends to said brake lever, a laterally flexible resilient arm carried by said trip lever, forming a continuation thereof and articulated to the pawl to exert yieldable rocking effort thereupon when the trip lever is actuated, and spring means urging said arm in a direction to rock said pawl into engagement with said ratchet.

2. A brake lever assembly comprising a ratchet plate having substantially segmentally arranged teeth, a brake lever fulcrumed on the plate substantially at the center of the segment, whereby the lever projects substantially radially from the ratchet plate, a pawl pivoted on the brake lever adjacent the teeth and having a working arm engageable with the teeth and which, when in engagement with the teeth, extends substantially parallel to the ideal arm of the lever but is swingable away from such engagement. a trip lever for actuating the pawl to released position pivoted on the brake lever and extending substantially parallel thereto and articulated to the pawl, a laterally flexible spring section forming a portion of said trip lever and yieldable in the direction in which effort is applied to the latter to release the pawl, whereby said trip lever may be actuated whether or not the pawl is movable F7 prevent movement thereof in either direction until said brake lever is moved bodily in a direction to rock the pawl toward released position sufficiently to free the same for full movement to released position under the influence of the energy stored in said spring section.

ALVIN L. JOHNSON.